Telephone-exchange system



Nov. 17, 1925- y w. c. KlEsEL TELEPHONE EXCHANGE SYSTEM Filed Oct. 3l. 1919 Patented Nov. 17, 1925.

uNiTED STATES PATENT OFFICE.

'W'AL'I'ER C. KIESEL, OF NEW YORK, Il. Y., ASSIGNOR TO ESTEB/N ELECTRIC COM- PANY, I NCOBFORATEDfOF NEW YORK,

Yy, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed October 3l, 1919.

private branch exchange syste-ins whereinl both manual and automatic facilities for interconnection are provided.

In such systems it is the usual practice to provide subscribers, desiring both manual and automatic facilities foi` interconnection, with two telephone sets, one of the manual type and the other of a t-ype so arranged that the subscriber may himself make the selection of the desired subscriber, an im? pulse sender being most commonly used. i

The object of this invention is to provide a single telephone set for extending a connection from a calling line to a called line over either a manual or an automatic link circuit and to provide means whereby saidk calling line may be signaled during the extension of a connection over said automatic link circuit. p V

A further object is to provide in a system of this character, means whereby, during the existence of a connection supervised by an operator, a subscriber may hold such connec' tion, call another station over automatic switching apparatus and after completion of conversation therewith resume conversation over the supervised connection, A c

In accordance with the objects of this invention, a' subscribers telephone set is provided with means whereby he may selectively extend his line to a manual switch board or to automatic switching apparatus. When the telephone set is connected to the latter, a signaling device located at the subscribers station .is automatically placed under the control of the operator at the manual switchboard. This signaling device serves also to hold the connection over the supervised connection when the switching device is operated for the purpose of making a call over the automatic switching mechanism.

A further feature is in a supervisory means actuated .ir response .1:9 .the plugging Serial No. 334,638.

into the jack in which such a subscribers station normally terminates for indicating to the operator that such a station is busy talking over the automatic link circuit.

Other novel and useful features will be i madeclearer in the following specification and the appended claims.

In the dra-wing, Fig. l, represents diagrammatically the circuits and apparatus embodied in this invention. That portion of j the drawing indicated by the dotted lines in.

the upper left-hand corner of the drawing yrepresents the apparatus necessary for a station equipped with means for extending the line to a manual switchboard or to automatic switching apparatus. A represents an orf dinary subscribers set, 5 is a switching device which for convenience is here shown as a key, S represents an ordinary subscribers impulse sender which may be of any type,

and a signaling means is here shown as a ringer 56. The subscribers set A is normally connected through the switching device 5 to a jack 7 located at the I. B. X. switchboard.` Substation B represents aline not equipped with special service features and has its jack multipled to the terminals of a contact bank.

Fig. 2 represents'diagrammatically a cord circuit of a wellknovvn type/ and is used for manually interconnecting the substations at the switchboard. Fig.`3 represents diagrammat-ically a substation of the I). B. X. system not arranged for special service features. The jacks in which such lines terminate are inultipled to the terminals of a contactbank, having an automatic switch cooperating therewith. The invention will be more readily understood from a detailed vdescription of the operation of the system.

The party at substation A desiring to call, for example, station B, operates the locking key 5 and then removes the receiver from the switchhook. Only one subscribers station of the system is assumed to be equipped with the special service features. If there were aplui'ality of such substations each would be equipped' with' a line finder (not shown). `Operation of key 5 extends the callingY line to the connector C. The stepping relay '8 thereof is energized and by attracting its armature energizes a slow revlease relay 19. relay in attracting its riglitarniature interposes a break in tliecircuit for release magnet RM and at its right armature and front contact connects the baclr contact of stepping relay 8 to the primary magnet PM of the connector. Vlhe calling party now operates his sender S to transmit the tens digit of the desired number. The sender in restoring, interrupts the line circuit a number of times corresponding to the tens digit of the desired number. Upon each retraction of the stepping relay 8, an impulse is sent over a circuit to primary magnet PM to position a set of brushes 11, 12 and 13 in operative relation to the group of terminals containing those of the lwanted line. This circuit entends from free pole of battery, magnet PM, side switch arm 1+i, back contact and armature 50 of busy Arelay 55, conductors 15 and Li6, right armature and'front'contact of relay 9, land armature and back contact of relay` S to ground. yThe slow relay 1Gin parallel with magnetPli/l energizes upon the first impulse, and vbeing slow-acting remains energized during the transmission of the impulses. When the sender S restores and maintains the line circuit closed, relay S remains energized. After an interval, the slow relay 16 becomes deenergizedopening the circuit of magnet 17 which was closed when this relay was energized. The escape magnet 17 in deeiier- `v'gizing mores t-he side switch into position vln this position the secondary magnet SM is sul'istit-uted for the priniary magnet Pill. The calling` party now operates his sender to transmit the units digit of the :desired number. Thesecondary magnet. SM in response to these impulses steps the brushes A11, 12 and 13 over -theterminals of the selected group. The slow `relay '-16 is again-'enerf gleed: in parallel with the secondary/magnet SM and again energizes the-escape magnet VVlhen the sender S-restores andmain- -tains thel line Acircuit closed,` the slow relayrl afteian/interval deenergizes, opening the cuit: grounded battery, escape-magnet 17, arm-22, armature and back contact of ringing eutsofl relay v29,conductors 23, 24 to .groundiat theleftrhand armature and front yContact of relay 9. vMagnet 17in attracting ,its armature closes the ringing circuit .as follows ground, generator 25, battery, re

lay 29, armature and front Contact. of maen a: net 11,. .arm l26and itstliird contact, brush ,12,.terminal 43, through the substation B,

terminal i2,.brush 11, Iarm 31 and` its third Contact to ground.

Whenthe party at substation Brenioves his receiifer, ,the .Delay 29 energizes, opening,r

the circuit of escape magnet 17, which tliere- `upon deenergizes and moves the side switch into position L1. In moving out of position 3, the ringing circuit is opened and in posh tion Lltalking current is supplied t-o the called party over the following circuit: grounded battery, retardation coil winding 33, conductor 3st, arm 31 and its fourth contact, brush 11, terminal l2, through substation B, terminal L13, brush 12, arm 26 and its fourth contact, conductoi' 35, retardation coil winding 3G to ground. Talking current is supplied to the calling party over the windings of relay 8. The calling and called ends of the talking circuit are conductively separated and inductively united by condensers 37 and 38.

Assume now that the line upon which the connector is set is busy.- The test terminal l0 in such eyent vould have a battery potential thereon, either due to another connector beingset upon said terminal or due to battery being supplied from the sleeve ofa cord circuit which had been plugged into 'ack of the line at the switchboard. Going :A: to that point in operation where the calling party transmits the units digit of the calle-:l number, it will be remembered that the slow relay 16 is energized in parallel with the secondary magnet SM, and that this relay at its armature and front contact completes a circuit for the escape magnet 1T, the side switch being at this time iu position lVhen the connector brushes 11, 12 and 13 reach the selected set ot' terminals 4.3 and 4&0, and before'lhe slow relay 1G has had time to retract its armature, a circuit is closed in position 2 vof the-side switch over terminal l0 of the busy line whiclihasfhat tery thereon, brush 13, vside switcharm 11 and its second Contact, right winding of reflay o5 toground through contacts 9S andV yRelay in attracting its inner armature locks itself up. over a sideswitch arr-l lland its second contact. ntfarniature 51 relay 55 closes a circuit to maintain Athe escape magnet 1'? energized. to Ihold the-sideswitch Vin position 2. At l.armature 50it interposes a break in the circuit of magnet SM to prevent the calling subscriber from transmitting-.any more impulses and 'at its outer lef"- .hand larmature connects a source of busy tone current 42 over side switch arm ,45%. in its. second positionto the conductor :iu/l thence tofthe calling line to` inform the calling party that the desired line .is busy. Then the calling ,party replaces his receiver, relays 8 and 9 release and the connector re* lease magnet RMis energized overt-he following'circuit: free, pole of battery, magnet RM, contact PON,-right armatures and bach contacts of relays 9 and S to ground. Mag netzRM restoreszthe connector Aand when the brnshshaft thereof reaches itsnornial position, it opens contact FON and unlocks the l. (il) lit) release magnet. This magnet in operating 'also restores the side switch in a well-known manner. Y

Suppose now that during the establish ment of a connection over the automatic switching mechanism with some station of Cil the private branch exchange system, a station at the central office desires connection with substation A. The operator places the calling plug 21 in jack 7, which causes the energization of relay 19, and of the bridged relay 18 in the cord circuit over the following circuit: ground, left-hand winding of relay 18, tip of plug 21, tip of jack 7, front contact and armature of relay 19, ringer 56, contact and upper outer spring of switching device 5, conductor 10, ring of jack 7, ring of plug 21, and right-hand winding of relay 18 to grounded battery. VEnergization of relay 18 causes lamp 17 of the cord circuit to light. This signifies to the operator that substation A is busy talking over the automatic switching apparatus to some other station of the private exchange system; she, therefore, informs the calling party that substation Av is busy. Suppose on the other 'hand that the incoming call for substation 'A 1s a very important one, or is perhaps a long distance call, the operator will in such case depress her ringing key (not shown), and send a source of ringing current to substation A over the following circuit: ring of plug 21, ring of ack 7, conductor 10. uppermost spring and Contact of switching device 5, ringer 16, contact of relay 19 (condenser 20 being short-circuited over conductor G), tip of jack 7, tip of plug 21 to source of ringing current. The ringer 5G will be operated and substation A will', therefore, be notified that a very important call for him has arrived. Conversation with substation B will then be terminated, switching device 5 will be restored and substation A is ready to talk with the calling line. Again suppose that a conversational connection exists over the manual link circuit M between subscribers A and D, or between subscriber A and a party at the central oflice, and that subscriber A desires information from some other substation of the private branch yexchange system. Operation of switching device 5 will bridge ringer 16 across the line leading to the cord circuit M so that no disconnect signal will be given to the operator at the switchboard. Impulse sender S will then be operated, connection completed over the automatic switching mechanism, and after information has been obtained or in structions have been given, the subscriber of substation A again restores switching device 5, reconnects his substation to substation C, and resumes conversation. After completion of conversation restoration of receiver upon the receiver hook gives the dis- .connect signal to the Operator in the usual manner who thereupon disconnects and the system is ready for anothercall.

That is claimed is: Y, 1. In a telephone exchange system, a

plurality of subscribers lines, a manual and an automatic connecting circuit for extendinga calling one of said lines to a called one of said lines, subscriber controlled switching means for selectively extending the calling line over said manual or said automatic connecting circuit, and a signaling device for the calling line placed in operative relationship with one of the connecting circuits in response to the actuation of the switching means to connect the calling line to the other of the connecting circuits.

2. In a telephone exchange system, a calling line, a signaling device associated with said calling line, a called line, a manually controlled circuit for interconnecting said lines, a circuit controlled by the calling line for establishing a connection with the called lin'e independently of the manually controlled circuit, and means for actuating said signaling device independently of the conductors of said calling line over the manually controlled circuit when said calling line is connected to the independently controlled circuit.

`3. In a telephone exchange system, a vcalling line, a called line, a manually controlled link circuit for interconnecting said lines, an automatic link circuit controlled by the calling line for establishing a connection with the called line independently of the manually controlled circuit, switching means at the calling line for selectively connecting. said line with one or the other of Vsaid link circuits, and a signal device at the calling Stationplaccd under the control of the manually controlled circuit in response to the actuation of the switching means to connect the calling line with the automatic link circuit.

4. In a telephone exchange system, a calling line, a station therefor, a switching device at the calling station, a called line, automatic switching mechanism for interconnecting said lines when said switching device is in one position, a manual circuit for connecting said lines when`said switching device is in another position, and means for signaling the calling station over the manual connecting circuit when the station of the calling line is connected to the automatic switching mechanism.

5. In a telephone exchange system, a calling line, an operator-s position, a switching device having a plurality of positions for connecting said line to a corresponding plurality of other lines, one of said other lines comprising a signaling conductor and a pair of talking conductors, said one of said other lines extending from said switching device to said operators position, and supervisory CII Cfl

means at said operators position controlled over said signaling conductor for indicating to the operator the position of said switching device.

6. In a telephone exchange system, a manual switchboard, operators cord circuits thereat, a calling line, a switching device having a plurality of positions for connecting said calling line to a corresponding plurality of other lines, one ot said other lines extending lrom said switching device to said manual switchboard and comprising a signaling conductor and a pair of talking conductors, and supervisory means associa-ted with said cord circuits controlled over said signaling conductor for indi ating to the operator the position oit said switching device.

7. In a telephone exchange system, a manual switchboard, a plurality oit telephone lines terminating in jacks therein, link circuits for interconnecting` said lines, a contact bank having its terminals multipled to said jacks, an automatic switch associated therewith, a calling line having two branches, one of said branches terminating` in a jack in said switchboard and the other in said automatic switch, a switching device for extending said calling line to said manual switchboard or to said automatic switch, and means ttor signaling' said calling line `from said manual switchboard during the extension of a connection over said antomatic switch.

8. In a telephone exchange system, a calling line, a called line, a plurality ot other lines, all of said lines terminating at the same manually operated switchboard, a manual link circuit for connecting` said calling line with said called line, an automatic link circuit ttor connecting said calling line with any of said other lines, and means t'or holding a connection over said manual circuit during the establishment of a connection to any ot said other lines over said automatic link circuit, said means serving as a signaling device to attract the attention of the subscriber of the calling line when a call is initiated over the automatic link circuit.

9. ln a telephone exchange system, a calling line, a called line, a plurality ot' other lines, all of said lines terminating` at the same manually operated switchboard, a manual link circuit for connecting said calling line with said called line, an automatic link circuit for connecting said calling line with any ot said other lines, a switching device arranged in its normal position to eX- tend said calling line to said manual link circuit and in its operated position to said automatic link circuit, and holding means tor said manual link circuit operative when said switching device is operated to extend said calling line to said automatic link circuit.

l0. ln a telephone exchange system, a plurality o't' lines,a manual and an automatic connecting circuit for extending one of said lines to another ot said lines, a switching device` 'for the calling line for ena-bling the calling subscriber to selectively extend his line over one or the other of said connecting circuits, and a signaling device placed in operative relationship with one of said connecting circuits in response t0 the seizure ot the other ot said connecting circuits.

' ln witness whereof' l hereunto subscribe my name this 30th day of October A. D.,

WALTER C. KIESEL. 

